Hybrid servo design for large area nano pattern stitching

Interference Lithography offers a low-cost alternative to the next-generation lithography (NGL) technology. Using ultra-violet light, the interference lithography could produce patterns with nano meter feature sizes. Because the working area of the focused laser is usually very small, it is necessary to repeat the exposure for large area applications. This research presents a precision 2D servo system to patch the successive lithography patterns together. The period of the pattern from the interference lithography is 600 nm. To achieve seamless patching, the system has to achieve the same stitching accuracy throughout the entire the length of the lithography pattern. In this research, the servo control system achieves typically less than 20 nm overall stitching accuracy to patch the patterns together.